Temmie is a species of monster in the Underground. They appear as a unique enemy in Waterfall, residents of Temmie Village, and the vendor of Tem Shop.
Contrary to popular belief, killing Temmie accrues EXP and is considered a kill by the game, which will cause a True Pacifist Route attempt to fail.
The Temmie are all girls and they are all named "Temmie" except for "Bob". They also resemble cat and dog.